Procedura: generare codice XML da file CSV
In questo esempio viene illustrato come utilizzare LINQ (Language-Integrated Query) e LINQ to XML per generare un file XML da un file CSV con valori delimitati da virgole.
Esempio
Il codice seguente consente di eseguire la query LINQ su una matrice di stringhe.
Nella versione per C# nella query viene utilizzata la clausola let per suddividere ogni stringa in una matrice di campi.
// Create the text file.
string csvString = @"GREAL,Great Lakes Food Market,Howard Snyder,Marketing Manager,(503) 555-7555,2732 Baker Blvd.,Eugene,OR,97403,USA
HUNGC,Hungry Coyote Import Store,Yoshi Latimer,Sales Representative,(503) 555-6874,City Center Plaza 516 Main St.,Elgin,OR,97827,USA
LAZYK,Lazy K Kountry Store,John Steel,Marketing Manager,(509) 555-7969,12 Orchestra Terrace,Walla Walla,WA,99362,USA
LETSS,Let's Stop N Shop,Jaime Yorres,Owner,(415) 555-5938,87 Polk St. Suite 5,San Francisco,CA,94117,USA";
File.WriteAllText("cust.csv", csvString);
// Read into an array of strings.
string[] source = File.ReadAllLines("cust.csv");
XElement cust = new XElement("Root",
from str in source
let fields = str.Split(',')
select new XElement("Customer",
new XAttribute("CustomerID", fields[0]),
new XElement("CompanyName", fields[1]),
new XElement("ContactName", fields[2]),
new XElement("ContactTitle", fields[3]),
new XElement("Phone", fields[4]),
new XElement("FullAddress",
new XElement("Address", fields[5]),
new XElement("City", fields[6]),
new XElement("Region", fields[7]),
new XElement("PostalCode", fields[8]),
new XElement("Country", fields[9])
)
)
);
Console.WriteLine(cust);
' Create the text file.
Dim csvString As String = "GREAL,Great Lakes Food Market,Howard Snyder,Marketing Manager,(503) 555-7555,2732 Baker Blvd.,Eugene,OR,97403,USA" & vbCrLf & _
"HUNGC,Hungry Coyote Import Store,Yoshi Latimer,Sales Representative,(503) 555-6874,City Center Plaza 516 Main St.,Elgin,OR,97827,USA" & vbCrLf & _
"LAZYK,Lazy K Kountry Store,John Steel,Marketing Manager,(509) 555-7969,12 Orchestra Terrace,Walla Walla,WA,99362,USA" & vbCrLf & _
"LETSS,Let's Stop N Shop,Jaime Yorres,Owner,(415) 555-5938,87 Polk St. Suite 5,San Francisco,CA,94117,USA"
File.WriteAllText("cust.csv", csvString)
' Read into an array of strings.
Dim source As String() = File.ReadAllLines("cust.csv")
Dim cust As XElement = _
<Root>
<%= From strs In source _
Let fields = Split(strs, ",") _
Select _
<Customer CustomerID=<%= fields(0) %>>
<CompanyName><%= fields(1) %></CompanyName>
<ContactName><%= fields(2) %></ContactName>
<ContactTitle><%= fields(3) %></ContactTitle>
<Phone><%= fields(4) %></Phone>
<FullAddress>
<Address><%= fields(5) %></Address>
<City><%= fields(6) %></City>
<Region><%= fields(7) %></Region>
<PostalCode><%= fields(8) %></PostalCode>
<Country><%= fields(9) %></Country>
</FullAddress>
</Customer> _
%>
</Root>
Console.WriteLine(cust)
L'output del codice è il seguente:
<Root>
<Customer CustomerID="GREAL">
<CompanyName>Great Lakes Food Market</CompanyName>
<ContactName>Howard Snyder</ContactName>
<ContactTitle>Marketing Manager</ContactTitle>
<Phone>(503) 555-7555</Phone>
<FullAddress>
<Address>2732 Baker Blvd.</Address>
<City>Eugene</City>
<Region>OR</Region>
<PostalCode>97403</PostalCode>
<Country>USA</Country>
</FullAddress>
</Customer>
<Customer CustomerID="HUNGC">
<CompanyName>Hungry Coyote Import Store</CompanyName>
<ContactName>Yoshi Latimer</ContactName>
<ContactTitle>Sales Representative</ContactTitle>
<Phone>(503) 555-6874</Phone>
<FullAddress>
<Address>City Center Plaza 516 Main St.</Address>
<City>Elgin</City>
<Region>OR</Region>
<PostalCode>97827</PostalCode>
<Country>USA</Country>
</FullAddress>
</Customer>
<Customer CustomerID="LAZYK">
<CompanyName>Lazy K Kountry Store</CompanyName>
<ContactName>John Steel</ContactName>
<ContactTitle>Marketing Manager</ContactTitle>
<Phone>(509) 555-7969</Phone>
<FullAddress>
<Address>12 Orchestra Terrace</Address>
<City>Walla Walla</City>
<Region>WA</Region>
<PostalCode>99362</PostalCode>
<Country>USA</Country>
</FullAddress>
</Customer>
<Customer CustomerID="LETSS">
<CompanyName>Let's Stop N Shop</CompanyName>
<ContactName>Jaime Yorres</ContactName>
<ContactTitle>Owner</ContactTitle>
<Phone>(415) 555-5938</Phone>
<FullAddress>
<Address>87 Polk St. Suite 5</Address>
<City>San Francisco</City>
<Region>CA</Region>
<PostalCode>94117</PostalCode>
<Country>USA</Country>
</FullAddress>
</Customer>
</Root>